At this point I dont think any of them need it.
But I think bringing back the shield every so often gets a pip and allows wwe to sell a bunch of t-shirts.
From a storytelling perspective because they are all faces and still friends, there's no reason not to do it. The shield were together prior to ambrose getting injured, and Seth and Roman continued to watch each others back semi regularly.
I don't think this,can ever be a permanent thing, but as long as it's a draw with the fans I think we'll see it appear in short bursts.